Thank heavens, for musicals. Based on Anita Loos' play, out of the novel written by Colette, Gigi snatched a ream of Academy Awards and promptly became the course of much debate and criticism for ever and a day it seems. The problem, as most musical aficionados will attest, is that Alan Jay Lerner and Frederick Loewe rehashed their previous stage hit "My Fair Lady". Which to an extent is true, hell they even slotted in one of "My Fair Lady's" thrown away songs, "Say A Prayer For Me Tonight", into Gigi's bubbly mix. But on its own terms, Gigi is still a vibrant and rewarding picture that…